The midimory package

There is a grid of buttons and each button plays a tone when pressed.
Every tone is connected to two buttons.
The players must find the pairs of buttons with equal tones.
The two players alternatingly test pairs of buttons.
If they select a pair of buttons with equal tones,
there score is increased by one.

In order to play the tones
you must connect it to a hardware or software synthesizer
like Timidity or FluidSynth.